Display screen or portion thereof with a graphical user interface for a digital card



The FIGURE is a front view of a display screen with a graphical user interface for a digital card.

The broken lines of the FIGURE depict portions of a user device and a display screen with a graphical user interface for a digital card. These broken lines depict environmental subject matter and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface for a digital card, as shown and described. 